3. Cameron Diaz

Diaz walks the beach in a delicious Lollipop suit from Le Doux. Call 888-284-2420 for stores or improvise her look with the Buttercup top in emerald green from L*Space and Bright Stripe bottoms from Salinas.
BUY ONLINE NOW Top, $61; at instyleswimwear.comBottoms, $60; at urbanoutfitters.com

5. Kate Hudson

Hudson emerges from the ocean in a simple but classic string bikini. Look sexy on the beach in similar separates from Cosabella Mare.
BUY ONLINE NOW Top, $60; at chicmystique.comBottoms, $60; at chicmystique.com

FlyNet

6. Keira Knightley

Knightley shows off her toned abs in a candy-striped bandeau suit. Get your bikini wardrobe in good shape with the Heart Breaker suit in red-and-white stripes from Wet Seal.
BUY ONLINE NOW Top, $19.50; at wetseal.com Bottoms, $19.50; at wetseal.com

Ginsburg/Spaly/Splash

7. Lindsay Lohan

Lindsay's bright blue bikini plays up her copper locks beautifully. Pick up the Essential triangle top and string-bikini bottoms from Gap in marine blue to get the young starlet's look.
BUY ONLINE NOW Top, $20; at gap.com Bottoms, $26.50; at gap.com

Will Binns/Andy Johnstone/Pacificcoast

8. Evangeline Lilly

The Lost star makes waves in bright floral separates. Get similar surfer-girl style in a beaded bikini from Op.
BUY ONLINE NOW $86; at victoriassecret.com

Bauer-Griffin

9. Sienna Miller

The British beauty plays it cool in the Torey suit from Vix. Chain detailing gives the nautical-inspired bikini some extra edge.
BUY SIENNA'S BIKINI NOW $122; at vixswimwear.com

Ginsburg/Spaly/Splash

10. Vanessa Minnillo

Minnillo shows off her incredible figure in a black suit with sexy accent rings. Play poolside peekaboo in the similar Kate Ring bikini from So De Mel.
BUY ONLINE NOW $150; at kateboutique.com

Kadena/Bauer-Griffin

11. Pink

Pink pairs her skull-printed triangle top with plain black bottoms for a little-yes, just a little-conservative touch. Get her style with a Rock n' Roll High Skull bikini top from Holmes Swimwear and hipster bottoms in black from L*Space.
BUY ONLINE NOW Top, $96 (sold as set); at susanholmes.netBottoms, $59; at everythingbutwater.com

Bret Thompsett/Pacificcoast

12. Christina Ricci

Ricci soaks up the sun with a girl's true best friends-a dog and a bright bikini. Try the look with a ruched-front bandeau top and solid bottoms in cinnabar from J. Crew.
BUY ONLINE NOW Top, $36; at jcrew.com Bottoms, $34; at jcrew.com

Pacificcoast

13. Nicole Richie

Richie piles on the accessories to add some color to a classic black two-piece. Buy a string bikini from Old Navy and you too can afford to splurge on some beach-chic baubles.
BUY ONLINE NOW Top, $16.50; at oldnavy.comBottoms, $16.50; at oldnavy.com

Splash

14. Rihanna

The songstress dresses up for a day at the beach in a chocolate-brown suit with jeweled detail. No need for an S.O.S.-the La Dolce Vita suit from Asha Couture will give you similar sparkle.
BUY ONLINE NOW $132; at swimwearboutique.com

Bret Thompsett/Pacificcoast

15. Molly Sims

Sims did Sports Illustrated proud in her colorful string suit. Get the former swimsuit-model's look with the Eye of the Tiger print top and keyhole bottoms from Love Surf Love.
BUY ONLINE NOW $86 at swimwearboutique.com

Madison/X17

16. Charlize Theron

Theron is the apple of her dogs' eyes in a striped string bikini. Fetch the Mackenzie suit in Blue Stripe from Abercrombie & Fitch for a Charlize-like look.
BUY ONLINE NOW Top, $34.50; at abercrombie.comBottoms, $34.50; at abercrombie.com

Andy Johnstone/Pacificcoast

17. Ashlee Simpson

Simpson wades in the water in a bright rugby-striped two-piece from Rusty. Get a similar effect with the Tennis Stripe halter top and tie bottoms from Juicy Couture.
BUY ONLINE NOW $140; at bloomingdales.com

Pacificcoast

18. Drew Barrymore

Barrymore wears her birthday suit-her Lisa Curran bandeau bikini birthday suit, that is. She bought the suit in two colors for a celebratory beachside bash.
BUY DREW'S BIKINI NOW $140; at shopbop.com

The actress sports a floral-print Diane von Furstenberg suit while bodyboarding in the Caribbean. Get this actress-tested bikini for your next day on the waves.
BUY PENELOPE'S BIKINI NOW Top, $80; at nordstrom.com Bottoms, $80; at nordstrom.com

Flynet

20. Denise Richards

The actress bares her famous bikini bod in a wine-colored two-piece from Vix. Get a similar look with the striped Neverland suit from Pompei Beach.
BUY ONLINE NOW $72; at instyleswimwear.com

Starsurf/Splash

21. Kirsten Dunst

Dunst keeps her cool in a black bandeau bikini topped with bright white shades from Luella. Get a similar look with separates from the Victoria's Secret Beach Sexy collection and sunnies from Fred Flare.
BUY ONLINE NOW Top, $15; at victoriassecret.com Bottoms, $14; at victoriassecret.comSunglasses, $9; at fredflare.com

Courtesy of net-a-porter.com

22. More Swimsuit Sites

Vivre.comTry this stylish site for sexy suits from Roberto Cavalli and more. Though the selection isn't huge, the unique suits are worth a look. Victoriassecret.comIf you’re a fan of their bras, you'll find the same styles and support in their bikini and tankini tops. Bottoms and tops are sold separately, so you can find the best fit for your figure. Net-a-porter.comTake your designer fetish to the beach! This site carries hot brands like Diane von Furstenberg, DampG, Missoni and Pucci in a variety of styles and splashy prints. At left: DampG Dolce amp Gabbana red-and-white striped bikini, $215; at net-a-porter.com.